Tohuku Electric Power Company’s Onagawa unit 2 is the thirteenth Japanese reactor – and the first boiling water reactor – to be restarted since the earthquake and tsunami of March 2011.
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Tokohu’s Onagawa plant (Image: Kurihalant Co Ltd)
The company said it restarted unit 2 at the plant in Japan’s northeastern Miyagi Prefecture at 7pm on Tuesday 29 October. “Going forward, we will continue with various inspections, tests, and work in preparation for the plant’s resumption of operation (power generation), which is expected to occur in early November 2024,” it said.
The Onagawa plant was the closest nuclear power plant to the epicentre of the earthquake and tsunami of 11 March 2011, but sustained far less damage than expected. The quake knocked out four of the plant’s five external power lines, but the remaining line provided sufficient power for its three boiling water reactors (BWRs)Â – the same type as those at the Fukushima Daiichi plant –Â to be brought to cold shutdown. The plant was largely unaffected by the tsunami as it sits on an elevated embankment more than 14 metres above sea level, although the basement floors of unit 2 were flooded.
Tohoku applied to the Nuclear Regulation Authority (NRA) in December 2013 for a safety assessment of Onagawa 2 to verify countermeasures applied at the plant meet new safety standards. In February 2020, the NRA approved the final screening report, clearing the way for the unit to resume operation. Tohoku was required to complete the countermeasure upgrades and obtain the approval of local authorities before restarting the unit.
Tohuoku President and CEO Kojiro Higuchi said the company has prioritised safety as it has proceeded towards the restart. “We will continue to prioritise ensuring safety as we thoroughly handle each and every process toward restarting the plant for the first time in 13 years,” he said.
“The restart of Onagawa Nuclear Power Plant Unit 2 will be the first restart of a boiling water reactor damaged in the Great East Japan Earthquake. We believe that this will not only contribute to the recovery from the earthquake disaster, but will also be of great significance in terms of ensuring a stable supply of electricity and contributing to carbon neutrality.
“Furthermore, we believe that the understanding of the local community is paramount when it comes to restarting operations, and we will continue to take every opportunity to thoroughly and clearly explain our efforts to the local community.”
Tohoku is in the process of seeking clearance to restart Onagawa unit 3, but announced in October 2018 that Onagawa unit 1 – the oldest unit at the site – would be decommissioned rather than upgraded.
Chugoku Electric Power’s Shimane unit 2 is set to become the second Japanese BWR to restart. The company announced this week it has begun fuel loading ahead of a restart that is planned for December.